i think the best and easiest method for create favicons(better than any plugin), that will work across all platforms and devices(mac, windows, mobile devices etc) is to use this awesome online resource, our designers at http://graphictoronto.com use this site for all of our web design projects, it's simple, fast and free!

First create your favicon file, 280x280 pixels, save it as a .png or .jpg then go to the web address listed below and follow the instructions!